Machine-switching telephone-exchange system



Janu 8 1924. I 1,480,241

H. P. cLAUsEN ET AL MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM Filed[Law Y 16, 1918 2 Sheets-Sheet 1 all I //7 yen 70/ MMA/fy.

Jan. 8 1924.

H. P. CLAUSEN ET AL MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM FiledJuly 1 1918 2 Sheets-Sheet 2 fly W A y- Patented Jan. 8, 1924.

UNITED STATES PATENT OFFICE.

HENRY P. CLAUSEN, OF IMOU'N'JI VERNON, AND CHARLES I. GOODRUM, OF NEWYORK, N. Y., ASSIGNOBS '10 WESTERN ELECTRIC COMPANY, INCORPORATED, OFNEW YORK, N. Y., A CORPORATION OF NEW YORK.

MACHINE-SWITCHING TELEPHONE-EXCHANGE SYSTEM.

Application filed m 16, 1918. Serial No. 245,145.

To all whom it may concern:

Be it known that we, HENRY P. CLAUsnN and CHARLES L. GOODRUM, citizensof the United States, residing at Mount Vernon,

6 in the county of VVestohester, State of New York, and at New York, inthe county of New York and State of New York, respectively, haveinvented certain new and useful Improvements in Machine-Switching Tele-10 phone-Exchange Systems, of which the following is a full, clear,concise, and exact description.

This invention relates to special service systems for machine switchingtelephone exchanges.

In systems employing so-called manual working, that is, where operatorsare employed for answering calls and for setting up connections, certainspecial service features have been developedwhich are of great value,especially in rivate branch exchange working. One of t ese features is ameans for summoning a particular person to the telephone when suchparticular erson is away from his instrument. Shou d a call come in to aprivate branch exchange and were the operator there requested tocomplete a connection to a particular person, say, for instance, thesuperintendent of the establishment wherein the private branch exchangeislocated, and should the particular person be at that time away fromhis instrument, the operator, after an appro: priate interval, would usea special means for summoning such particular person. This special meansis in the present day practice dissociated with the telephone sys temand such service is not supplled by the telephone companies. It,however, is a valuable feature and one which, from its nature, should beretained in machine switching telephone exchan es installed for privatebranch exchange wor ing.

The object of the present invention is to provide means whereby acalling party may summon a particular person when such particular personis away from his instrument.

Accordingly, a signal circuit is wired up throughout the building inwhich the private branch exchange apparatus is installed whereby signalsmay be transmitted which will attract the called party wherever he is.This signal system is preferably in the form of a code signalingarrangement with one code representing each particular person who may beprovided with this special SGI'VICB feature.

Associated with each telephone is a means for operating this signalcircuit automaticallyso that, if a particular person who is called doesnot answer his telephone within a reasonable time, a simple manipulationof the dial switch under the control of which the connection isoriginally set up, will set the signal circuit in operation to transmitthe particular code corresponding with the telephone station called. Theinvention is illustrated in the drawings in two figures. Fig. 1 showsdiagrammatically a calling sub-station, a connector switch, a calledsubstation and a signal bell code ringing apparatus, and Figure 2 showsa second calling substation adjacent to one of the bells on the callbell circuit.

Briefly, the operation is as follows: The calling subscriber atsub-station 1, desiring to communicate with theparty who should be atsubstation 2, sets up the connection in the usual manner whereupon thetelephone bell at substation 2 commences to ring. If, after a certainperiod, the subscriber at substation 1 concludes that the party atsubstation 2 is not there, he will manipulate his dial switch from anyone of the finger holds, whereupon the call bell apparatus, consistingof the constantly rotating cams 3 and 4 and the circuit 5 including thecall bells 6 and 7, will be actuated. Thereupon, the bells 6 and 7throughout the building in which this private branch exchange may beinstalled, will commence to ring in code. The party who should be atsubstation 2 hearing the ringing of the bells and recognizing theparticular code as summons for himself, goes to the nearest telephone 8in the building and calls a special number. This special number is oneknown to himself only andit connects him to a set of multiple terminalsconnected with his own line at substation 2. Thereupon, the ringing ofthe telephone bell at substation 1 is discontinued and conversationtakes place between the calling substation 1 and the substation 8.

At the end of the conversation both parties hang up and the apparatus inthe automatic switches is all restored in the ordinary manner. 7 Itis'thoughtthe operation as a Whole may be more clearly understoodthrough the following detailed description. I

The subscriber at substation 1, after removing his receiver from itshook, causes the extension of his line in the usual manner by automaticswitches until the connector switch of Figure 1 is seized; thereupon,the calling line relay 9 will be energized-and in turn the first slowrelay 10 Wlll be energized. A manipulation of the dial sw1tch at thecalling substation 1 now causes the line relay 9 to vibrate its armatureand a circuit on each back stroke is set up from ground, through thearmature and back contact of the relay 9, the right-hand armature andfront contact of the relay 10, thereafter in one direction through thewinding of second slow relay 11, to battery and round, and in the otherdirection through side-switch wiper 12 in its first position, primarymagnet 13, to battery and ground. Primary magnet 13 responds to eachimpulse separately but the slow releasing relay 11 responds to the trainof impulses as a whole. Primary magnet 13 causes the stepping of thebrushes 14c, 15, 16 and 17 in a primary direction' whereby a particulargroup of lines is selected. Slow releasing relay 11 by attracting itsarmature energizes the escape magnet 18 through a circuit extending fromground, through armature and back contact of relay 19, winding of relay18, right-hand arm ature and front contact of relay 11, to battery andground. At the end of this series of impulses, slow releasing relay 11,being deprived of energizing current for a suflicient length of time,retracts its armatures and in so doing opens the circuit for the escapemagnet 18, whereupon the sideswitch wipers are passed into their secondposition and the connector switch is ready to receive the last set ofimpulses. When this is sent in response to the manipulation of the dialswitch at the calling substation 1, the armature of-relay 9 is vibratedas before and upon each back stroke a circuit is established which nowextends through the secondary magnet 20 instead of, as before, theprimary magnet 13. Slow releasing relay 11 is energized, as before, andthe escape magnet 18 is also energized as before. Upon each energizationof the secondary magnet 20, the brushes 14 to 17 inclusive, are steppedin their secondary direction until the selected line is reached."whereupon a test is made. At the end of this series of impulses, slowreleasing relay 11 again retracts its armature and by deenergizing theescape magnet 18 causes the side-switch wipers to move into their thirdposition.

It will be noticed that escape magnet 18 is slow to release and thattherefore before the side-switch wipers have passed to their thirdposition, a circuit is established from the second position contact ofthe side-switch nector switch.

e an be returned to normal but the other automatic switches in the trainwill not be released since the test wire will be grounded over theleft-hand winding, left-hand armature and contact of release magnet 23,the left-hand armature and front contact of relay 10 and the testterminal 25 of the conlthrough this circuit the release magnet willremain energized and thereupon a busy tone will be transmitted from thesource of busy tone BZ to one side of the line and thence to the callingline in the usual manner. If, on the other hand, the called line isfound to be idle, then upon the release of the escape magnet 18, thesideswitch arms would have been advanced to their third position and theescape magnet 18 would again be energized over a circuit from ground,the armature and contact of relay 19, winding of escape magnet 18,sideswitch arm 26 and its third position contact, to battery and ground.Through the energization of escape magnet 18 the bell at the calledsubstation 2 is rung through the flow of ringing current at the contactof escape magnet 18, through its armature, winding of relay 19, thirdposition contact and sidesWitch Wiper 27, brush 15,- terminal 28, theline to the called substation 2 through the bell at the calledsubstation back over the other side of the called line, terminal 29.brush 14, side-switch arm 30 and its third position contact, frontcontact and armature of line relay 9, to ground.

Should the called subscriber be within hearing distance of his owntelephone bell and should he in answer to its summons remove hisreceiver from his hook, he would cause a suflicient flow of ringingcurrent through the relay 19 to open the circuit of the escape magnet18, whereupon the sideswitch wipers would be'passed into their fourthpositions and the conversational circuit established in the ordinarymanner.

During the conversational period the calling subscriber is supplied withtalking current through the windings of the line relay 9 and the calledsubscriber is supplied with talking current through the windings of thecalled supervisory relay 31.

At the close of the conversation the calling subscriber by hanging uphis receiver deenergizes the line relay 9, in response to which relay 10becomes deenergized, whereupon a circuit is established from groundthrough armature and back contact of relay 9, righthand armature andback contact of relay 10, left-hand armature and back contact of relay10, the off-normal contact 22, the righthand winding of release magnet23, to batter'v and ground, whereupon the connector switch is releasedin the manner hereinbefore described.

If, on the other hand, the subscriber who should be at substation 2 isin some other part of the building and does not answer the summons ofhis telephone bell, the calling subscriber 1 may manipulate his dialswitch from any one of its finger holds, thereupon, remembering that theside-switch wipers are in their third positions during the ringingperiod, a circuit will be established from ground, through the armatureand back contact of relay 9, the right-hand armature and front contactof relay 10, the side-switch wiper 12 and its third position contact,the brush 17, terminal 32, winding of relay 33, to battery and ground.Relay 33 locks up over a circuit from battery and ground through thewinding of relay 33, its left-hand contact, the back contact andarmature of relay 34, terminal 24, brush 16, sideswitch wiper 21, andits third position contact, to ground. This closes a circuit includingthe spring contact 35 working in conjunction with the code ringing cam3, whIch is constantly rotating, through the front contact andright-hand armature of relay 33, thence over the circuit 5 including thecode ringing call bells 6 and 7. The call bells throughout the building,illustrated by two, that is, Nos. 6 and 7, ring continuously until thecalled subscriber is attracted thereby, and proceeds to set up aconnection to his own line. This he may do by going to any substationsuch as No. 8 and dialing a special number. In response to the dialingoperations at substation 8, a circuit will be established between thesubstation 8 and the connector switch 36 which is in all respectssimilar to the connector switch in Fig. 1.

In response to further manipulations of the dial at substation 8,.thebrushes 37, 38, 39 and 40 may be set on the special number correspondingto the called subscribers substation. The terminals 41 and 42 completecircuits which willcause the ringing current being transmitted atpresent from both connector switches to be cut off and to cause theside-switch wipers of both connectors to be advanced to position 4. Inone case this circuit may be traced from the source of ringing currentconnected to the contact of escape magnet 18 through its armature,winding of relay 19, third position contact and side-switch 27, thebrush 15, terminal 28, the conductor 44, terminal 41, brush 37,side-switch wiper 45 and its third position contact, front contact .andarmature of line relay 46, to round. This causes the energization of t erelay 19 and as before described the passing of the side-switch wipersof the connector switch shown in Fig. 1 into their fourth ositions. In asimilar manner the relay 4 in the connector switch 36 is energized overthe conductor 48 and the side-switch wipers of the connector 36 arepassed into their fourth positions, whereupon conversation between thesubstation 1 and the substation 8 may proceed.

As the connector switch 36 sets its brushes 37 to 40 inclusive, on theterminals 41, etc., representing the special number corresponding withthe called substation 2, a circuit is completed from ground, throughthird position contact and side-switch wiper 49, brush 39, terminal 43,winding of relay 34, to battery and ground. Relay 34 in attracting itsarmature opens the circuit of the code ringing control relay 33, wherebyit is deenergized and the code ringing on the circuit 5 is cut off.

At the close of the conversation when the receiver at the substation 1is replaced on its hook, the calling relay 9 is deenergized and theconnector switch in Figure 1 is released, and when the receiver atsubstation 8 is replaced the calling line relay 46 is deenergized andthe connector switch 36 is released.

Another s'ubstation 50 is shown to illustrate how this special servicemay be supplied so that an oflicial of a higher rank may take precedenceover anofiicial of a lower rank. Should a call come in for an ofiicialwhose substation is No. 50 and in the manner described should the callbell circuit 5 be set in operation through the energization of relay 51,the operation may go on as herein described. If, however, before theoflicial who should be at substation. 50 has picked up the call to histelephone in the manner described, another call comes in for theofficial who should be at substation 2 and who is presumed to be ofhigher rank, then the energization of relay 33 will cut off from 'thecall bell circuit the train of impulses set up by the cam 4 andsubstitute therefor trains of impulses set up. by the cam 3. In thismanner the higher of the two ofiicials will be served first.

The call bell circuit 5 may be of any suitable form but is here merelyindicated as a cam disc such as 3 or 4 which operates the spring contactto close the circuit in a characteristic manner. A grounded contact isshown in cooperative relation with the spring 35 and the circuit 5proceeding from the call bell 7 is shown in a dotted line indicatingthat it goes through several more call bells such as 6 and 7 and thenceto a suitable source of battery supply. Instead of call which willattract the attention of a person, may be used.

Another valuable special service feature present in this arrangement isthe following: Terminals 29, 28, 24 and 32 of the called substation 2represent one set of the multiple terminals appearing in the connectorswitches which have access to this line. Terminals 41, 42 and 43represent one set of another series of multiple terminals which appearin the same connector switches. The first set may be reached throughdialing one number and the second set may be reached through dialinganother number. The first set are the regular terminals of thesubstation 2 and are those which are reached through the calling of thissub-station by its listed number. The number used for reaching thesecond set is to be known only to the subscriber who should be atsubstation 2 and anyone else Whom he may trust with this number.

When a connection is established to substation 2 through the first setof terminals 29, 28, 24 and 32, calls to this substation through thisset of multiple terminals are barred, but calls to the substationthrough the other set of multiple terminals are not barred. Since thetest terminal 43 remains ungrounded, therefore, a trusted lieutenant maybreak in on the circuit of substation 2, even though it be busy in anestablished connection. If, however, such trusted lieutenant hasestablished a connection through the number known only to himself andhis superior, that is, through the terminals 41 to 43, the grounding ofthe terminal 43, and consequent energization of the relay 34 will barnot only calls to this substation through the group of multipleterminals of which 41 to 43 are a set, but also calls coming in throughthe roup of terminals of which 29, 28, 24 and 32 are a set. Theenergization of relay 34 through its front contact, grounds the multipleterminal 24 and the terminal 43 is grounded through the side switchwiper 49 in its fourth position.

What is claimed is: o

1. In a telephone system, telephone lines each including a callingsignal, a secondary calling signal common to said lines, meansindividual to each of said. lines for automatically operating saidsecondary calling signal in a difierent characteristic manner, means forselecting said lines and operating said signals, and means responsive toan additional operation of said selecting means for subsequently causingthe actuation of said first means.

2. In a telephone system, telephone lines, a signal individual to eachof said lines, a signal common to said lines, separate means foractuating said common and said individual signals, machine switchingmeans for interconnecting said lines, means whereby auser a first one ofsaid lines may call a second one or said lines and actuate saidindividual signal of said second line, means whereby said first line maythereafter actuate said common signal, means whereby a third one of saidlines may establish a conversational circuit to said first line, andmeans responsive to the establishment of said conversational circuit forcausing the operation oil said individual signal and said common signalto cease.

3. ln a telephone system, telephone lines, an individual signal for eachof said lines, a common signal for said lines, means associated witheach of said lines for operating said common signal in a distinctivemanner,

machine switching means for establishing a connection between a firstone of said lines and a second one of said lines, means included in saidmachine switching means for causing said individual signal of saidsecond line to operate, means under control of said calling line forsubsequently causing said common signal to operate, means whereby athird one of said lines may establish a conversational circuit to saidfirst line, and means responsive to the establishment of such connectionfor causing the operation of said individual and common signals tocease.

4. Tu a telephone system, telephone lines, an individual signal for eachof said lines, a common signal for said lines, means associated witheach of said lines for causing said common signal to operate in adistinctive manner, machine switching means for interconnecting saidlines, means included in said machine switching means responsive to theestablishment of a connection between two of said lines for causing theindividual signal of the called one of said lines to operate, meansunder control of the calling one out said lines for thereafter causingthe common signal to operate in such amanner as to identify the calledone of said lines, means whereby a second connection may be establishedthrough said machine switching means between a third one of said linesand said pair of lines involved in said first-mentioned connection, andmeans responsive to such an established connection for causing theoperation of said individual and common signals to cease.

5. lln a telephone system, telephone lines,- a signal individual to eachof said lines, a signal common to said lines, means individual to eachof said lines for causing said common signal to operate in a distinclllUcommon signal to operate in a predetermined order of preference toidentify said lines whose individual signals are operating. 6. In atelephone system, telephone lines,

5 a signal common to said lines, means asso ciated with each of saidlines for causing said signal to operate in a distinctive manner, andmeans responsive to the simultaneous operation of several of said linesfor causing said common signal to identify each of said lines in apredetermined order of preference.

7. In a telephone system, telephone lines,

each includin a primary calling signal,

means for cal ing said lines and actuating said signals a secondarycalling signal common to said lines, and means dependent on themaintenance of an established connection to one of said lines forsubsequently selectively actuating said secondary signal.

In testimony whereof We hereunto sub scribe our names this 8th day ofJuly A. D.,

HENRY P. CLAUSEN. CHARLES L. GOODRUM.

